title: Role of electronic correlation in high-low temperature phase transition of hexagonal nickel sulfide: a comparative density functional theory study with and without correction for on-site Coulomb interaction.
abstract: The structural, electronic, magnetic, and elastic properties of hexagonal nickel sulfide (NiS) have been investigated comparatively by Density Functional theory (DFT) and DFT plus correction for on-site Coulomb interaction (DFT+U), in which two different exchange correlation functionals local density approximations (LDA) and general gradient approximations (GGA) in the form of Perdew-Burke-Ernzerhof (PBE) are used. Our results indicate LDA and PBE methods predict hexagonal NiS to be a paramagnetic metal whereas LDA(PBE)+U calculations with reasonable on-site Coulomb interaction energy give the antiferromagnetic insulating state of low temperature hexagonal NiS successfully. Meanwhile, compared with LDA(PBE) results, LDA(PBE)+U methods give larger lattice parameters, crystal volume, and shear constant c44, consistent with the experimental picture during high-low temperature phase transition of hexagonal NiS, in which an increase of the shear constant c44 and lattice parameters were found in the low-temperature antiferromagnetic phase. The present DFT and DFT+U calculations provide a reasonable description for the properties of high temperature and low temperature hexagonal NiS respectively, which indicates that electronic correlation is responsible for this high-low temperature phase transition.
authors.affiliation: School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410004, People's Republic of China. zhangwb@csust.edu.cn
authors.forename: Wei-Bing
authors.initials: WB
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Bi-Yu
authors.initials: BY
authors.lastname: Tang
mesh_terms: D004583:Electrons; D009532:Nickel / Q000737:chemistry*; D044367:Phase Transition; D011789:Quantum Theory; D013696:Temperature
chemical_list: D009532:Nickel; C017558:nickel sulfide